Gut Immune Cells Link Menopause to Bone Loss: AIIMS Study

A new study by Dr Rupesh K Srivastava, Additional Professor, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS) and his team has uncovered a strong connection between gut health and bone strength, offering promising insights for women at risk of developing osteoporosis after menopause.

Srivastava’s group has discovered that a group of immune cells in the gut, known as regulatory T cells (Tregs), plays a key role in maintaining bone health. After menopause, falling estrogen levels disturb the balance of these immune cells, triggering inflammation that speeds up bone breakdown.

The team also discovered that under estrogen-deficient conditions, a subset of these Tregs (RORγT-pTregs), which are normally protective immune cells, can turn into harmful Th17 cells that promote bone loss. However, when mice were given Lactobacillus acidophilus, a beneficial bacterium found in probiotics, their bone health improved.

This probiotic helped restore immune balance in the gut, in a butyrate (gut-associated metabolite)-mediated manner that reduced inflammation likely by preventing the transdifferentiation of RORγT-pTregs to Th17 cells.

The findings highlight how beneficial gut bacteria are to both immune and bone health, suggesting that probiotics could become a natural approach to help prevent or manage postmenopausal osteoporosis.


Speaking to Health Dialogues, Dr Srivastava said that their findings show that gut health is very closely linked to bone health.

Que: How strongly is gut health linked to bone health, especially during and after menopause?


Dr Srivastava: Our results show that gut health is very closely linked to bone health. During menopause, lower estrogen levels weaken the gut lining, disturb healthy gut bacteria, and increase immune-mediated inflammation in the body. All these factors promote bone loss and raise the risk of fractures.

Que: Can probiotics like Lactobacillus acidophilus genuinely help prevent bone loss in postmenopausal women? If yes, how should they be taken safely?

Dr Srivastava: Yes, probiotics such as Lactobacillus acidophilus can protect bones in postmenopausal women by keeping the gut healthy and reducing inflammation. They are usually found to be safe when taken daily, either as a good-quality supplement or through fermented foods like yoghurt or curd.

Que: Are there specific signs that my gut immune system or Treg cells are out of balance and could be affecting my bones?


Dr Srivastava: There is no single clear symptom that directly shows a Treg cell imbalance. Digestive problems like bloating or indigestion may suggest something is off, but this imbalance can usually only be confirmed through immune testing done in a laboratory.

Que: Besides probiotics, what lifestyle or dietary changes can support gut bacteria and reduce inflammation that leads to bone loss?


Dr Srivastava: Our results show that probiotics mainly function by boosting the production of various metabolites in the gut, such as short-chain fatty acids (SCFAs), bile acids, etc. This effect could further be enhanced by diets which support the growth of these probiotic bacteria in the gut, suchas  fibre-rich foods (vegetables, fruits, and whole grains, along with fermented foods and healthy fats), and thus can help enhance overall bone health.


Que : Should postmenopausal women consider gut microbiome testing as part of osteoporosis risk assessment?

Dr Srivastava: Yes, this is part of our ongoing study, where we are examining changes in the composition of gut bacteria (healthy vs inflammatory) in postmenopausal women. Our goal is to create a clear “map” of the gut microbiome in postmenopausal osteoporosis, which can serve as a reference to help identify women at higher risk of bone loss, thereby supporting earlier diagnosis and therapy for osteoporosis and related fractures.